1. Technical Field
This device relates to specialized power equipment for the removal and replacement of manhole assemblies. Such equipment has been developed that simplify the removal and installation of sanitary manhole configurations including chimney reconstruction in accordance with the compliance of state and local specifications.
2. Description of Prior Art
Prior art devices of this type have been directed towards initially hand held cutters used to cut the chimney liner used to adjustably position the manhole casing on the support cone. A variety of bracket assemblies have been developed to support and guide cutting elements within the manhole. Other support mounted manhole cutting devices can be seen in combination with removal and preparation tools in U.S. Pat. Nos. 4,924,951, 6,539,987, and 6,709,064.
In U.S. Pat. No. 4,924,951 a manhole cutter is disclosed that is inserted into an existing manhole to a depth sufficient to engage and remove the manhole by clamping thereto and cutting from the inside surface.
U.S. Pat. No. 6,539,987 is a quick manhole construction method wherein a cutting unit is lowered into the manhole engaging the inside surface cuts with the removal of the manhole casing.
U.S. Pat. No. 6,709,064 claims a method and device for detaching or cutting out an embedded manhole frame having a cutter attached to the manhole performing eccentric circumferential runs along the inside thereof for removal.
An example of a commercially available device that is known which is directed towards the cutting of the plastic forms used to extend the mounting surface from the manhole “cone” and are left in place after cutting. The device is manufactured by the Whirly Gig Company shown in an informational print-out exhibit A in which a router type tool is mounted on an arm that extends from a central support shaft held by a pair of cross brackets extending outwardly over the manhole to support same.